Auto merge of #13553 - birtles:animvalues, r=Manishearth

Support creating StyleAnimationValue objects from Servo

These are the servo-side changes for [bug 1302949](https://bugzilla.mozilla.org/show_bug.cgi?id=1302949#c59). @Manishearth has already reviewed them there.

---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix [bug 1302949](https://bugzilla.mozilla.org/show_bug.cgi?id=1302949#c59)
- [X] These changes do not require tests because there are existing tests for this in mozilla-central

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---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/13553)
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components/style/gecko/wrapper.rs

@@ -70,6 +70,16 @@ pub struct GeckoDeclarationBlock {
     pub immutable: AtomicBool,
 }
 
+impl PartialEq for GeckoDeclarationBlock {
+    fn eq(&self, other: &GeckoDeclarationBlock) -> bool {
+        match (&self.declarations, &other.declarations) {
+            (&None, &None) => true,
+            (&Some(ref s), &Some(ref other)) => *s.read() == *other.read(),
+            _ => false,
+        }
+    }
+}
+
 unsafe impl HasFFI for GeckoDeclarationBlock {
     type FFIType = bindings::ServoDeclarationBlock;
 }

components/style/gecko_bindings/bindings.rs

@@ -165,6 +165,7 @@ use gecko_bindings::structs::nsINode;
 use gecko_bindings::structs::nsIDocument;
 use gecko_bindings::structs::nsIPrincipal;
 use gecko_bindings::structs::nsIURI;
+use gecko_bindings::structs::nsString;
 use gecko_bindings::structs::RawGeckoNode;
 use gecko_bindings::structs::RawGeckoElement;
 use gecko_bindings::structs::RawGeckoDocument;
@@ -399,6 +400,11 @@ extern "C" {
                                               *const ::std::os::raw::c_char,
                                           aLength: u32) -> bool;
 }
+extern "C" {
+    pub fn Gecko_Utf8SliceToString(aString: *mut nsString,
+                                   aBuffer: *const u8,
+                                   aBufferLen: usize);
+}
 extern "C" {
     pub fn Gecko_FontFamilyList_Clear(aList: *mut FontFamilyList);
 }
@@ -847,6 +853,18 @@ extern "C" {
                                                  reference:
                                                      RawServoStyleSheetBorrowed);
 }
+extern "C" {
+    pub fn Servo_ParseProperty(property_bytes: *const u8,
+                               property_length: u32,
+                               value_bytes: *const u8,
+                               value_length: u32,
+                               base_bytes: *const u8,
+                               base_length: u32,
+                               base: *mut ThreadSafeURIHolder,
+                               referrer: *mut ThreadSafeURIHolder,
+                               principal: *mut ThreadSafePrincipalHolder)
+    -> ServoDeclarationBlockStrong;
+}
 extern "C" {
     pub fn Servo_ParseStyleAttribute(bytes: *const u8, length: u32,
                                      cache: *mut nsHTMLCSSStyleSheet)
@@ -860,6 +878,11 @@ extern "C" {
     pub fn Servo_DeclarationBlock_Release(declarations:
                                               ServoDeclarationBlockBorrowed);
 }
+extern "C" {
+    pub fn Servo_DeclarationBlock_Equals(a: ServoDeclarationBlockBorrowed,
+                                         b: ServoDeclarationBlockBorrowed)
+     -> bool;
+}
 extern "C" {
     pub fn Servo_DeclarationBlock_GetCache(declarations:
                                                ServoDeclarationBlockBorrowed)
@@ -929,6 +952,11 @@ extern "C" {
     pub fn Servo_RestyleSubtree(node: RawGeckoNodeBorrowed,
                                 set: RawServoStyleSetBorrowedMut);
 }
+extern "C" {
+    pub fn Servo_RestyleWithAddedDeclaration(declarations: ServoDeclarationBlockBorrowed,
+                                             previous_style: ServoComputedValuesBorrowed)
+     -> ServoComputedValuesStrong;
+}
 extern "C" {
     pub fn Servo_GetStyleFont(computed_values:
                                   ServoComputedValuesBorrowedOrNull)

ports/geckolib/Cargo.lock

@@ -3,6 +3,7 @@ name = "geckoservo"
 version = "0.0.1"
 dependencies = [
  "app_units 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -407,6 +408,7 @@ name = "stylo_tests"
 version = "0.0.1"
 dependencies = [
  "app_units 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "geckoservo 0.0.1",

ports/geckolib/Cargo.toml

@@ -11,6 +11,7 @@ crate-type = ["staticlib", "rlib"]
 
 [dependencies]
 app_units = "0.3"
+cssparser = {version = "0.7"}
 env_logger = "0.3"
 euclid = "0.10.1"
 lazy_static = "0.2"

ports/geckolib/glue.rs

@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use app_units::Au;
+use cssparser::{Parser, ToCss};
 use env_logger;
 use euclid::Size2D;
 use parking_lot::RwLock;
@@ -29,17 +30,22 @@ use style::gecko_bindings::bindings::{RawServoStyleSheetStrong, ServoComputedVal
 use style::gecko_bindings::bindings::{ServoDeclarationBlockBorrowed, ServoDeclarationBlockStrong};
 use style::gecko_bindings::bindings::{ThreadSafePrincipalHolder, ThreadSafeURIHolder};
 use style::gecko_bindings::bindings::{nsHTMLCSSStyleSheet, ServoComputedValuesBorrowedOrNull};
+use style::gecko_bindings::bindings::Gecko_Utf8SliceToString;
 use style::gecko_bindings::bindings::RawServoStyleSetBorrowedMut;
 use style::gecko_bindings::ptr::{GeckoArcPrincipal, GeckoArcURI};
 use style::gecko_bindings::structs::{SheetParsingMode, nsIAtom};
 use style::gecko_bindings::structs::ServoElementSnapshot;
 use style::gecko_bindings::structs::nsRestyleHint;
+use style::gecko_bindings::structs::nsString;
 use style::gecko_bindings::sugar::ownership::{FFIArcHelpers, HasArcFFI, HasBoxFFI};
 use style::gecko_bindings::sugar::ownership::{HasSimpleFFI, Strong};
 use style::parallel;
-use style::parser::ParserContextExtraData;
-use style::properties::{ComputedValues, parse_one_declaration};
+use style::parser::{ParserContext, ParserContextExtraData};
+use style::properties::{ComputedValues, Importance, PropertyDeclaration};
+use style::properties::{PropertyDeclarationParseResult, PropertyDeclarationBlock};
+use style::properties::{cascade, parse_one_declaration};
 use style::selector_impl::PseudoElementCascadeType;
+use style::selector_matching::ApplicableDeclarationBlock;
 use style::sequential;
 use style::string_cache::Atom;
 use style::stylesheets::{Origin, Stylesheet};
@@ -91,6 +97,7 @@ fn restyle_subtree(node: GeckoNode, raw_data: RawServoStyleSetBorrowedMut) {
         LocalStyleContextCreationInfo::new(per_doc_data.new_animations_sender.clone());
 
     let shared_style_context = SharedStyleContext {
+        // FIXME (bug 1303229): Use the actual viewport size here
         viewport_size: Size2D::new(Au(0), Au(0)),
         screen_size_changed: false,
         generation: 0,
@@ -120,6 +127,35 @@ pub extern "C" fn Servo_RestyleSubtree(node: RawGeckoNodeBorrowed,
     restyle_subtree(node, raw_data);
 }
 
+#[no_mangle]
+pub extern "C" fn Servo_RestyleWithAddedDeclaration(declarations: ServoDeclarationBlockBorrowed,
+                                                    previous_style: ServoComputedValuesBorrowed)
+  -> ServoComputedValuesStrong
+{
+    match GeckoDeclarationBlock::as_arc(&declarations).declarations {
+        Some(ref declarations) => {
+            let declaration_block = ApplicableDeclarationBlock {
+                mixed_declarations: declarations.clone(),
+                importance: Importance::Normal,
+                source_order: 0,
+                specificity: ::std::u32::MAX,
+            };
+            let previous_style = ComputedValues::as_arc(&previous_style);
+
+            // FIXME (bug 1303229): Use the actual viewport size here
+            let (computed, _) = cascade(Size2D::new(Au(0), Au(0)),
+                                        &[declaration_block],
+                                        false,
+                                        Some(previous_style),
+                                        None,
+                                        None,
+                                        Box::new(StdoutErrorReporter));
+            Arc::new(computed).into_strong()
+        },
+        None => ServoComputedValuesStrong::null(),
+    }
+}
+
 #[no_mangle]
 pub extern "C" fn Servo_StyleWorkerThreadCount() -> u32 {
     *NUM_THREADS as u32
@@ -338,6 +374,54 @@ pub extern "C" fn Servo_StyleSet_Drop(data: RawServoStyleSetOwned) -> () {
     let _ = data.into_box::<PerDocumentStyleData>();
 }
 
+
+#[no_mangle]
+pub extern "C" fn Servo_ParseProperty(property_bytes: *const u8,
+                                      property_length: u32,
+                                      value_bytes: *const u8,
+                                      value_length: u32,
+                                      base_bytes: *const u8,
+                                      base_length: u32,
+                                      base: *mut ThreadSafeURIHolder,
+                                      referrer: *mut ThreadSafeURIHolder,
+                                      principal: *mut ThreadSafePrincipalHolder)
+                                      -> ServoDeclarationBlockStrong {
+    // All this string wrangling is temporary until the Gecko string bindings land (bug 1294742).
+    let name = unsafe { from_utf8_unchecked(slice::from_raw_parts(property_bytes,
+                                                                  property_length as usize)) };
+    let value_str = unsafe { from_utf8_unchecked(slice::from_raw_parts(value_bytes,
+                                                                       value_length as usize)) };
+    let base_str = unsafe { from_utf8_unchecked(slice::from_raw_parts(base_bytes,
+                                                                      base_length as usize)) };
+    let base_url = Url::parse(base_str).unwrap();
+    let extra_data = ParserContextExtraData {
+        base: Some(GeckoArcURI::new(base)),
+        referrer: Some(GeckoArcURI::new(referrer)),
+        principal: Some(GeckoArcPrincipal::new(principal)),
+    };
+
+    let context = ParserContext::new_with_extra_data(Origin::Author, &base_url,
+                                                     Box::new(StdoutErrorReporter),
+                                                     extra_data);
+
+    let mut results = vec![];
+    match PropertyDeclaration::parse(name, &context, &mut Parser::new(value_str),
+                                     &mut results, false) {
+        PropertyDeclarationParseResult::ValidOrIgnoredDeclaration => {},
+        _ => return ServoDeclarationBlockStrong::null(),
+    }
+
+    let results = results.into_iter().map(|r| (r, Importance::Normal)).collect();
+
+    Arc::new(GeckoDeclarationBlock {
+        declarations: Some(Arc::new(RwLock::new(PropertyDeclarationBlock {
+            declarations: results,
+            important_count: 0,
+        }))),
+        cache: AtomicPtr::new(ptr::null_mut()),
+        immutable: AtomicBool::new(false),
+    }).into_strong()
+}
 #[no_mangle]
 pub extern "C" fn Servo_ParseStyleAttribute(bytes: *const u8, length: u32,
                                             cache: *mut nsHTMLCSSStyleSheet)
@@ -362,6 +446,13 @@ pub extern "C" fn Servo_DeclarationBlock_Release(declarations: ServoDeclarationB
     unsafe { GeckoDeclarationBlock::release(declarations) };
 }
 
+#[no_mangle]
+pub extern "C" fn Servo_DeclarationBlock_Equals(a: ServoDeclarationBlockBorrowed,
+                                                b: ServoDeclarationBlockBorrowed)
+                                                -> bool {
+    GeckoDeclarationBlock::as_arc(&a) == GeckoDeclarationBlock::as_arc(&b)
+}
+
 #[no_mangle]
 pub extern "C" fn Servo_DeclarationBlock_GetCache(declarations: ServoDeclarationBlockBorrowed)
                                                  -> *mut nsHTMLCSSStyleSheet {
@@ -378,6 +469,39 @@ pub extern "C" fn Servo_DeclarationBlock_ClearCachePointer(declarations: ServoDe
     GeckoDeclarationBlock::as_arc(&declarations).cache.store(ptr::null_mut(), Ordering::Relaxed)
 }
 
+#[no_mangle]
+pub extern "C" fn Servo_DeclarationBlock_SerializeOneValue(
+    declarations: ServoDeclarationBlockBorrowed,
+    buffer: *mut nsString)
+{
+    let mut string = String::new();
+
+    if let Some(ref declarations) = GeckoDeclarationBlock::as_arc(&declarations).declarations {
+        declarations.read().to_css(&mut string).unwrap();
+        // FIXME: We are expecting |declarations| to be a declaration block with either a single
+        // longhand property-declaration or a series of longhand property-declarations that make
+        // up a single shorthand property. As a result, it should be possible to serialize
+        // |declarations| as a single declaration. However, we only want to return the *value* from
+        // that single declaration. For now, we just manually strip the property name, colon,
+        // leading spacing, and trailing space. In future we should find a more robust way to do
+        // this.
+        //
+        // See https://github.com/servo/servo/issues/13423
+        debug_assert!(string.find(':').is_some());
+        let position = string.find(':').unwrap();
+        // Get the value after the first colon and any following whitespace.
+        let value = &string[(position + 1)..].trim_left();
+        debug_assert!(value.ends_with(';'));
+        let length = value.len() - 1; // Strip last semicolon.
+
+        // FIXME: Once we have nsString bindings for Servo (bug 1294742), we should be able to drop
+        // this and fill in |buffer| directly.
+        unsafe {
+            Gecko_Utf8SliceToString(buffer, value.as_ptr(), length);
+        }
+    }
+}
+
 #[no_mangle]
 pub extern "C" fn Servo_CSSSupports(property: *const u8, property_length: u32,
                                     value: *const u8, value_length: u32) -> bool {

ports/geckolib/lib.rs

@@ -5,6 +5,7 @@
 
 #[macro_use]extern crate style;
 extern crate app_units;
+extern crate cssparser;
 extern crate env_logger;
 extern crate euclid;
 extern crate libc;

tests/unit/stylo/Cargo.toml

@@ -13,6 +13,7 @@ doctest = false
 
 [dependencies]
 app_units = "0.3"
+cssparser = {version = "0.7"}
 env_logger = "0.3"
 euclid = "0.10.1"
 lazy_static = "0.2"

tests/unit/stylo/lib.rs

@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 extern crate app_units;
+extern crate cssparser;
 extern crate env_logger;
 extern crate euclid;
 extern crate geckoservo;